Attachment B RST-PROP-SPEC-0123-.pdf

RST-PROP-SPEC-0123, Revision - Expiration Date: November 13, 2020

RST-PROP-SPEC-0123, Revision -

Roman Space Telescope (RST), Code 448

RST Propulsion Fill and Drain Valve Specification

National Aeronautics and Space Administration

Goddard Space Flight Center Greenbelt, Maryland

Roman Space Telescope Reviewed– Not Subject to Export Control

GSFC RST CMO

November 13, 2020

Released

RST Fill and Drain Valve Spec RST-PROP-SPEC-0123, Revision - Effective Date: November 13, 2020 ii

RST Fill and Drain Valve Specification Signature/Approval Page

Prepared By:

Eric Golliher

Approved By:

Betsy Forsbacka

Electronic Approval available on-line in the RST CM Tool file://gs448share/WFIRST/01.0%20Project%20Management/1.4%20Configuration-Data%20Mgmt/Templates/Document%20Templates/TDMS/Templates%20(boilerplates)/Historical/in iii

Preface This document is a Roman Space Telescope (RST) Configuration Management (CM)-controlled document.

Note: Prior to May 20, 2020, the project name was Wide Field Infrared Survey Telescope

(WFIRST).

For the purposes of configuration management, the prefixes “WFIRST” and “RST” are completely interchangeable. For example, RST-MGMT-PROC-0024 is the same as WFIRST-

MGMT-PROC-0024.

Changes to this document require prior approval of the applicable Configuration Control Board (CCB) Chairperson or designee. Proposed changes shall be submitted to the RST CM Office (CMO), along with supportive material justifying the proposed change.

In this document, a requirement is identified by “shall,” a good practice by “should,” permission by “may” or “can,” expectation by “will,” and descriptive material by “is.”

Questions or comments concerning this document should be addressed to:

RST Configuration Management Office Mail Stop 448 Goddard Space Flight Center Greenbelt, Maryland 20771 iv

Change History Log

Revision Effective Date Description of Changes (Reference the CCR & CCB/ERB Approval Date)

Revision - November 9, 2020 Per CCR-0292 Initial Release v

Table of Contents

1 INTRODUCTION

1.1 Purpose

1.2 Scope

1.3 Related Documentation

Applicable Documents

2 CONTRACT DESCRIPTION

2.1 Propellant Fill and Drain Valve Description

3 FUNCTIONAL/PERFORMANCE REQUIREMENTS

3.1 Fill and Drain Valve Flight Unit Functional/Performance Requirements Pressure

3.1.1.1 Maximum Expected Operating Pressure (MEOP)

3.1.1.2 Proof Pressure

3.1.1.3 Burst Pressure

3.1.1.4 Interface Tube Design Pressure

Pressure Transients Flow Rate and Pressure Drop Sealing

3.1.4.1 Seal Replacement

3.1.4.2 Inadvertent Stem Removal

3.1.4.3 Lock Wire Capability

3.1.4.4 External Cover Lanyard Capability

Leakage

3.1.5.1 Primary Seat Closed, AN Cap removed, and External Cover Removed

3.1.5.2 Primary Seat Open, AN Cap Installed, and External Cover Removed

3.1.5.3 Primary Seat Open, AN Cap Removed, and External Cover Installed

3.1.5.4 Primary Seat Closed, AN Cap Installed, and External Cover Installed

3.2 Resource Allocations

Mass Allocation

4 PHYSICAL REQUIREMENTS

4.1 Interface Documentation

Mechanical Interface Fluid Interface AN Fitting Threads

4.2 Mass Properties

Component Masses Center of Mass Location Center of Mass Accuracy Determination of Moments and Products of Inertia

4.3 Physical Envelope

4.4 Mounting

5 ENVIROMENTAL REQUIREMENTS

5.1 Quasi-Static Acceleration

5.2 Frequency Requirement

vi

Fundamental Launch Frequencies

5.3 Vibration

Sinusoidal Vibration Random Vibration

5.4 Shock

5.5 Pressure

Operating Pressure Range

5.6 Ground Environments

5.7 Thermal Requirements

Flight Interface Design Temperature Limits

6 CLEANLINESS

6.1 Surface Contamination

Surface Contamination Levels at Delivery

6.1.1.1 External Surface Contamination

6.1.1.2 Internal Surface Cleanliness

Surface Contamination Generation

6.1.2.1 Particulate Generation

6.1.2.2 Molecular Generation

Cleanability

6.1.3.1 Cleanability – Sensitive Surfaces

6.1.3.2 Cleanability – Sensitive Surface Cleaning Methods

6.1.3.3 Transportation Cleanliness

7 DESIGN & CONSTRUCTION REQUIREMENTS

7.1 Parts, Materials & Processes (PMP)

Materials

7.1.1.1 Material Conductivity

7.1.1.2 Lubricants

7.1.1.3 Fluid Compatibility

7.1.1.4 Fill and Drain Valves Dewpoint

7.2 Safety

7.3 Identification and Marking

7.4 Workmanship

Workmanship Standards Welding

7.5 Reliability and Mission Lifetime

Mission Life Shelf Life

7.6 Ground Handling

GSE Cleanliness

7.7 Interchangeability

8 MECHANICAL DESIGN REQUIREMENTS

8.1 Mechanical Factors of Safety

8.3 Metallic Pressurized Lines and Fittings Burst Factor

8.4 Materials

Dissimilar Metals vii

Material Allowables and Stiffness CTE Data Stress Corrosion Cracking

8.5 Joints

Joint Edge Distance Bonded Joint Allowable Reserved Fastened Joints

8.5.4.1 Fastener Locking

8.5.4.2 Fastened Joint Margin of Safety

8.5.4.3 Installation Torque Documentation

8.5.4.4 Seal Analysis

8.5.4.5 Critical Fasteners

9 LOGISTICS

9.1 Transportation Cleanliness

9.2 Transportability

9.3 Transportation Equipment

10 VERIFICATION REQUIREMENTS

10.1 Verification Methods

Inspection Analysis Test

10.2 Inspection Requirements

Visual Inspection Physical Measurement Documentation Search

10.3 Analysis Requirements

10.4 Test Requirements

Definitions Test Factors Proof Testing Factors Test Tolerances Test Restrictions

10.4.5.1 Failure During Tests

10.4.5.2 Modification of Hardware

10.4.5.3 External Adjustment

10.4.5.4 Re-Test Requirements

10.5 Required Tests

Performance Tests

10.5.1.1 Leakage

10.5.1.2 Flow Rate/Pressure Drop

Mass Properties Measurement Static Loads/Strength Test

10.5.3.1 Sine Burst

10.5.3.2 Static Pull

viii

Frequency Signature Survey Sine Vibration Random Vibration Proof Pressure Test Shock Thermal Cycling Testing

10.5.9.1 Thermal Vacuum Test Parameters

10.5.9.2 Thermal Cycle Test Profile

Appendix A Abbreviations and Acronyms

RST Fill and Drain Valve Spec RST-PROP-SPEC-0092, Revision A ix

List of Tables

Table 4-1: Interface Tube Requirements Table 4-2: Assignments for Variable Thread Mating Requirements Table 5-1 Fill and Drain Valve Design Limit Loads Table 5-2 Fill and Drain Valve Generic Sine Vibration Environment Table 5-3 Random Vibration Limit Levels for Components Weighing Less Than 22.7 kg Table 5-4 Minimum Workmanship ASD Level for Components Weighing Less than 45.4 kg. . 15 Table 5-5 Shock Limit Levels Table 5-6 Temperature Limits at Fill and Drain Valve Mounting Interface Table 5-7 Propellant-wetted In-flight Software Temperature Limits Table 8-1 Design Factors of Safety Table 8-2 Minimum Edge Distance Table 10-1 Test Factors and Durations Table 10-2 Proof Test Factors Table 10-3 Test Tolerances Table 10-4 Thermal Vacuum Test Parameters

List of Figures

Figure 1 Thermal Cycle Profile

RST Fill and Drain Valve Spec RST-PROP-SPEC-0123, Revision-

1 INTRODUCTION

1.1 Purpose

The Nancy Grace Roman Space Telescope (RST) is a mission responding to the 2010 National Research Council New Worlds, New Horizons (NWNH) Astronomy and Astrophysics Decadal Survey top priority recommendation in the large space mission category. The science program includes two dedicated investigations to tackle outstanding questions in dark energy research and exoplanet exploration, and includes a substantial General Observer program to enable targeted investigations of astrophysical phenomena to advance other goals from the Decadal Survey. A coronagraph instrument is included in the payload for purposes of advancing the present state of the art of coronagraph technology. This document defines the requirements for the Fill and Drain Valve.

1.2 Scope

This specification describes the electrical, mechanical, environmental, and verification testing requirements for a space-qualified Fill and Drain Valve for the NASA Goddard Space Flight Center (GSFC) RST Mission.

1.3 Related Documentation

RST documents can be obtained in the RST CM Tool. RST documents can be obtained from URL: https://ipdtdms.gsfc.nasa.gov.

Applicable Documents

The following documents and drawings in effect on the day this specification was signed shall apply to the fabrication and to the electrical, mechanical, and environmental requirements of the Fill and Drain Valve to the extent specified herein. In the event of conflict between this specification and any referenced document, this specification will govern, with the exception of the RST Fill and Drain Valve Statement of Work (RST-PROP-SOW-0052), in which case the Statement of Work takes precedence.

The following is a list of the applicable specifications and publications.

Document Number Title

RST-PROP-SOW-0052 RST Fill and Drain Valve Statement of Work RST-PROP-LIST-0115 RST Fill and Drain Valve Deliverable Items List and

Schedule (DILS) NASA-STD-8719.24 NASA Expendable Launch Vehicle Payload Safety

Requirements NASA-STD-5001B Structural Design And Test Factors Of Safety For spaceflight Hardware

Document Number Title

NASA-STD-6016A Standard Materials and Processes Requirements for spacecraft

NASA-HDBK-7005 Dynamic Environment Criteria NASA-STD-7001 Payload Vibroacoustic Test Criteria IEST-STD-CC1246E Product Cleanliness Levels – Applications, Requirements, and Determination GSFC-STD-7000A General Environmental Verification Standard (GEVS) NASA-STD-5019A Fracture Control Requirements for spaceflight

Hardware NASA-STD-5020A Requirements for Threaded Fastening Systems in spaceflight Hardware 541-WI-5330.1.41 Fastener Locking Using Arathane 5753 MIL-PRF-26536G Performance Specification Propellant, Hydrazine JSC-SPEC-C-20C Water, High Purity, Specification for MIL-PRF-27401G Propellant, Nitrogen, Pressurizing Agent MIL-PRF-27407D Propellant, Helium, Pressurizing Agent MIL-PRF-27415C Propellant Pressurizing Agent, Argon FED-STD-TT-I-735 Isopropyl Alcohol ASTM E-595-15 Standard Test Method for Total Mass Loss and

Collected Volatile Condensable Materials from Outgassing in a Vacuum Environment

ASTM A269 Standard Specification for Seamless and Welded Austenitic Stainless Steel Tubing for General Service

AMS 5647 Aerospace Material Specification for 304L Stainless Steel

AWS D17.1 Specification for Fusion Welding of Aerospace Applications

MSFC-STD-3029A Guidelines for the Selection of Metallic Materials for Stress Corrosion Cracking Resistance in Sodium Chloride Environments

AS4395A Fitting End, Flared Tube Connection, Design Standard RST-SYS-PLAN-0051 RST Contamination Control Plan

2 CONTRACT DESCRIPTION

2.1 Propellant Fill and Drain Valve Description

The propulsion subsystem fill and drain valves allow for the filling and draining of the spacecraft fluids, including test fluids, gaseous pressurant, and propellant. The subsystem requires two types of fill and drain valves, gas and liquid, which are designated A and B. There will be four

(4) liquid valves, one for each of the four tanks. Each connects to the hydrazine (liquid propellant) side of the diaphragm. There will be one (1) gas valve, which is common the gas (Helium) side for all four tanks. The remaining two (2) are propulsion subsystem spares, one gas spare and one liquid spare valve. In addition, one (1) additional liquid valve will be used for flush of test fluid (water) during the wet vibe and also planned to be used in the case of on-orbit refueling of the spacecraft.

Eight (8) Fill and Drain Valves are required for the RST mission. Please refer to the Statement of Work (SOW, RST-PROP-SOW-0052) and the Deliverable Items List and Schedule (DILS, RST-PROP-LIST-0115) for a complete list of all hardware, verification testing, test reports, and analyses that should be delivered with or before the Fill and drain valve.

Designation Function Operational Fluid(s) Qty.

Valve A Gas (1/4” AN Inlet

Fitting) Fill, Drain, and Test

Gaseous Nitrogen (GN2); Gaseous Helium (GHe); Gaseous Argon (GAr); High-Purity Hydrazine vapors;

Valve B Liquid (5/16” AN Inlet

Fitting) Fill, Drain, and Test

Gaseous Nitrogen (GN2); Gaseous Helium (GHe); Gaseous Argon (GAr); High-Purity Hydrazine liquid; Deionized Water

Each fill and drain valve shall include caps and seals required to seal the valve both in the closed position and when open with propellant flowing. Additionally, assorted Army and Navy (AN) fitting threads corresponding to the various operational fluids will be used to ensure proper operation.

If needed, the vendor will offer, as an option, a qualification plan that designates one (1) protoflight valve and tests to the qualification levels listed in this document. Valve designs that have been qualified previously shall include qualification documentation as described in the Statement of Work RST-PROP-SOW-0052

3 FUNCTIONAL/PERFORMANCE REQUIREMENTS

This section defines the functional and performance requirements for the Fill and Drain Valve as defined in Section 2.1.

3.1 Fill and Drain Valve Flight Unit Functional/Performance Requirements

Pressure

3.1.1.1 Maximum Expected Operating Pressure (MEOP)

The MEOP shall be 550 psia.

3.1.1.2 Proof Pressure

Proof pressure capability of the Fill and Drain Valve shall be at least 825 psia. This is a proof factor of 1.5.

If necessary, the proof pressure shall also include a factor to account for any difference in material properties between the proof test temperature and the operating temperature range.

3.1.1.3 Burst Pressure

Burst pressure of the propellant Fill and Drain Valve shall be at least 1375 psia. This is a burst factor of 2.5.

Burst pressure is the pressure that, once applied to the particular fill and drain valve, results in exceeding its ultimate strength.

3.1.1.4 Interface Tube Design Pressure

3.1.1.4.1 Proof Pressure

The interface tube design proof pressure capability shall be at least 825 psia. This is a proof factor of 1.5.

3.1.1.4.2 Burst Pressure

The interface tube design burst pressure capability shall be at least 2200 psia. This is a burst factor of 4.0.

Pressure Transients

The Fill and Drain Valve shall be designed to withstand near-instantaneous pressure increases from 100 psia to MEOP in the closed position without any degradation of performance.

Flow Rate and Pressure Drop

The liquid fill and drain valves shall be capable of providing a flow rate of 0.068 kg/s (0.15lb/s) H2O with a maximum pressure drop of 20 psid.

The gas fill and drain valves shall be capable of providing a flow rate of 0.0016 m3/s (3.4 scfm) GHe with a maximum pressure drop of 10 psid.

Sealing

Each valve shall contain at least three (3) seals when the primary seal is closed and both the AN cap and external cover are installed.

3.1.4.1 Seal Replacement

All seals, including the dynamic portion of the primary seal, shall be replaceable while the valves are installed on the S/C.

3.1.4.2 Inadvertent Stem Removal

All valves shall be designed to prevent inadvertent stem removal.

3.1.4.3 Lock Wire Capability

All seals on each fill and drain valve shall contain a provision for lock wires to ensure that they remain in place throughout the life of the mission.

3.1.4.4 External Cover Lanyard Capability

The external cover for each fill and drain valve shall contain provisions for attaching a lanyard without degrading the sealing ability of the cover.

Leakage

3.1.5.1 Primary Seat Closed, AN Cap removed, and External Cover Removed

Each valve shall demonstrate a total leakage rate of no greater than 1 x 10-6 sccs of GHe at the valve's MEOP with the primary seat closed to flight torque, AN cap removed, and external cover removed.

3.1.5.2 Primary Seat Open, AN Cap Installed, and External Cover Removed

Each valve shall demonstrate a total leakage rate of no greater than 1 x 10-5 sccs of GHe at the valve's MEOP with the primary seat open, AN cap installed, and external cover removed.

3.1.5.3 Primary Seat Open, AN Cap Removed, and External Cover Installed

Each valve shall demonstrate a total leakage rate of no greater than 1 x 10-5 sccs of GHe at the valve's MEOP with the primary seat open, AN cap removed, and external cover installed.

3.1.5.4 Primary Seat Closed, AN Cap Installed, and External Cover Installed

Each valve shall demonstrate a total leakage rate of no greater than 1 x 10-6 sccs of GHe at MEOP with the primary seat closed to flight torque, AN cap installed to flight torque, and external cover installed to flight torque.

Opening Design

Each seal shall be designed to prevent inadvertent opening.

Ease of Operation

Each valve shall be designed to be operable by one wrench. It can be assumed that the spacecraft structure is robust enough to resist the applied torque.

Cycles

The fill and drain valves shall be qualified for at least 150 open/close cycles at the expected operating pressures and temperatures.

3.2 Resource Allocations

Mass Allocation

The Fill and Drain Valve shall have a mass of less than or equal to 0.3 kg (0.66 lbm) including the cap.

4 PHYSICAL REQUIREMENTS

4.1 Interface Documentation

The contractor shall use metric units when interfacing with NASA GSFC including any drawings, documents, models, except for the following cases:

• SI units with parenthetical English units are permitted for engineering and manufacturing drawings.

• Angular measurement may be expressed in degree of arc or in an appropriate subdivision of degree of arc such as minute or second of arc (arc-min or arc-sec).

• Hardware that has been previously built, or new hardware of similar design heritage, may be specified in English units where use of metric equivalents would lead to additional risk and cost to the program, but interfaces with that hardware must use metric with parenthetical English units.

• Fasteners: Although bolt patterns will be defined using metric dimensioning, use of English fasteners (with hole dimensioning and tolerancing) is permitted.

• Heritage Component: Components that has been previously qualified, or of similar design heritage, may be specified in English units where use of metric equivalents would lead to additional cost to the program.

Mechanical Interface

The mounting interface shall be defined in the Mechanical Interface Control Drawing (MICD), which will be developed between the contractor and NASA GSFC COR.

Fluid Interface

Each valve shall contain an interface tube that shall have a length of no less than 2.0 inches (5.1 cm). The required interface tube characteristics for each fill and drain valve are given in Table 4-1:

Table 4-1: Interface Tube Requirements

Valve Interface Tube Dimensions Material

A 0.25” (0.64 cm) OD with a 0.028” (0.07 cm) wall thickness

304L Stainless Steel per ASTM- A511, or AMS-QQ-S-763

B 0.25” (0.64 cm) OD with a 0.028” (0.07 cm) wall thickness

304L Stainless Steel per ASTM- A511, or AMS-QQ-S-763

AN Fitting Threads

Each type of fill and drain valve shall have different AN fitting thread dimensions per AS- 4395A to differentiate between valve applications and working fluids.

The two AN fitting threads shall be assigned as shown in Table 4-2.

The contractor shall supply the acceptable torque range to avoid damage to the valve threads.

This range shall be included in the Fill and Drain Valves Operational Constraints Document, which is described in the Fill and Drain Valve Statement of Work (SOW), RST-PROP-SOW- 0052.

Table 4-2: Assignments for Variable Thread Mating Requirements

Valve Working Fluid Mating Thread Dimension A GN2, GHe, GAr SAE AS4395-G04 (0.25”) B GN2, GHe, GAr, Hydrazine, Water SAE AS4395-G05 (0.3125”)

4.2 Mass Properties

Component Masses

See section 3.2.1

The mass of the propellant fill and drain valve shall be measured to within 0.05 kg (0.11 lbm).

Center of Mass Location

The contractor shall define the center of mass in the Mechanical ICD.

Center of Mass Accuracy

The Center of mass shall be determined to within +/- 5 mm relative to an external reference.

Determination of Moments and Products of Inertia The final moments of inertia of the propellant fill and drain valve shall be calculated to within 1%.The final products of inertia of the propellant fill and drain valve shall be calculated to within 5%.

4.3 Physical Envelope

Each fill and drain valve, not including the interface tube, shall have a cylindrical envelope with an outer diameter (OD) of less than 2.0 inches (5.1 cm), a total length of less than 6.25 inches (15.88 cm).

This envelope shall encompass the valve, the AN cap, external cover, and mounting flange. The interface tube shall not be considered part of the physical envelope.

4.4 Mounting

The Fill and Drain Valve will be hard-mounted on a mechanical surface of the spacecraft structure. The mounting interface shall be defined in the MICD.

5 ENVIROMENTAL REQUIREMENTS

Environmental design requirements for the spacecraft components are specified in this section.

The Fill and Drain Valve shall meet its performance requirements in section 3.0 during and after exposure to the environments specified in this section.

5.1 Quasi-Static Acceleration

Quasi-static acceleration represents the combination of steady-state accelerations and the low frequency mechanically transmitted dynamic accelerations that occur during launch.

The Fill and Drain Valve shall be designed to withstand the quasi-static design limit loads defined in the mass-acceleration curve (MAC) shown in Table 5-1without damage or degradation of performance. The design loads shown below will be updated based on the results of coupled loads analysis.

Note:

1. For masses within the breakpoints, linear interpolation is used to determine load.

2. Loads are considered to act in any direction, one axis at a time.

Table 5-1 Fill and Drain Valve Design Limit Loads

Component Mass (Kg) Limit Load (g)

0.5 35.9 1 35

5.2 Frequency Requirement

Fundamental Launch Frequencies

The Fill and Drain Valve shall have a fundamental frequency greater than 100 Hz when hard mounted at its spacecraft interface.

Note:

1. Requirements are met assuming rigid stiffness to restrained Degree of Freedom (DOF).

2. Components with first fundamental frequency greater than 75 Hz may verify through low level signature tests. Components with a frequency less than 75 Hz are required to perform modal testing and provide a test correlated FEM for dynamic analysis. Requirements for the FEM are in the SOW.

3. Frequency requirements apply to all modes with modal effective mass fraction (MEMF) >5% of FEM mass. MEMF is compared to the total mass of the element/subsystem/component, not against higher levels of assembly. e.g. OBS modes MEMF is compared to OBS mass

4. For modes with MEMF between 5% and 10% that do not meet the frequency requirement(s), additional assessments can be made by the observatory systems group to determine the effects of the mode on observatory dynamics and subsystem/element design limit loads.

5.3 Vibration

Sinusoidal Vibration

The Fill and Drain Valve shall withstand the sinusoidal vibration levels defined in herein.

1. Levels defined are acceptance levels. Analysis is conducted against acceptance with the safety factors defined in Table 8-1. Testing factors are defined in Table 10-1.

2. Peak levels at the low end of the frequency range (5 - 20 Hz) may be ramped up as needed to accommodate table limitations.

3. The sine sweep vibration levels are defined at the interface of the element/subsystem.

4. Input levels may be notched to limit the test specimens CG response to 1.25 times its

Design Limit Load outlined in Table 5-1.

5. Test verification is required over the range 5 to 50 Hz. Analytical verification is required from 50 to 100 Hz.

6. Elements/Subsystems/components with a first fundamental frequency equal to or greater than 75 Hz can forgo sine vibration testing from 5 to 50 Hz, while verification through analysis of the 50 to 100 Hz is still required.

7. Subsystems/components with a fundamental frequency equal to or greater than 150 Hz can forgo the sine vibration environment until higher levels of assembly upon approval by the

NASA/GSFC COR.

Table 5-2 Fill and Drain Valve Generic Sine Vibration Environment

Frequency (Hz) Limit Level

5 to 100 10.0 g

Levels may be notched such that the interface forces do not exceed 1.25 times the design limit load outlined in section 5.1. Peak levels at the low end of the frequency range (5 – 20 Hz typically) may be ramped up as needed to accommodate shaker table displacement limitations.

Flight, Acceptance level 0.50 in (double amplitude) can be adjusted to accommodate vibration table limitations, with approval from the NASA/GSFC COR.

Random Vibration

a. The Fill and Drain Valve shall withstand the random vibration environment applied at the interface to the Fill and Drain Valve.

The random vibration inputs are based on GEVS and may be notched to limit the test article’s cg response to 1.25 times DLL. Notched inputs must envelope minimum workmanship levels in order to screen for design or manufacturing flaws. A delicate optic, detector, sensor, etc., which is shown analytically to have negative margin at minimum workmanship levels may notch further at those frequency bands with project concurrence.

Table 5-3 shows the limit level random vibration environment for components with mass less than 22.7 kg. Analysis is conducted against acceptance with the safety factors defined in Table 8-1. Testing factors are defined in Table 10-1.

Table 5-4 defines minimum workmanship for components weighing less than 45.4 kg. Random vibration specs may be updated based on acoustic analysis.

During testing, force limiting control is recommended and the control method must be approved by the NASA/GSFC COR.

Table 5-3 Random Vibration Limit Levels for Components Weighing Less Than 22.7 kg

Frequency (Hz) ASD Limit Level (g2/Hz)

20 0.013 20 - 50 +6 dB/oct

50 - 800 0.08 800 - 2000 -6 dB/oct

2000 0.013 Overall 10.0 grms

Table 5-4 Minimum Workmanship ASD Level for Components Weighing Less than 45.4 kg.

Frequency (Hz) ASD Level (g2/Hz)

20 0.01 20 - 80 +3 dB/oct

80 - 500 0.04 500 - 2000 -3 dB/oct

2000 0.01 Overall 6.8 grms

5.4 Shock

The Fill and Drain Valve shall be designed to meet its performance requirements after being subjected to the shock environment, applied at the Fill and Drain Valve interface to the RST spacecraft structure. Levels defined are acceptance levels. Testing factors are defined in 10.4.2.

Table 5-5 Shock Limit Levels

Frequency (Hz) Limit Load (g)

100 75 100 – 738 6.5 dB/oct

738 858 10000 858

Note: A shock susceptibility and attenuation assessment is to be performed on Fill and Drain Valve. This assessment can be based on past shock tests or other relevant information.

5.5 Pressure

Operating Pressure Range

The Fill and Drain Valve shall be designed to meet all performance requirements while operating over a pressure range of 813 Torr to 1 x 10-14 Torr.

5.6 Ground Environments

The Fill and Drain Valve shall meet all of their performance requirements during exposure to air temperature between +5 and +30 degrees C and relative humidity between 30% and 70%.

5.7 Thermal Requirements

Flight Interface Design Temperature Limits

The Fill and Drain Valve shall demonstrate operational capability at the Minimum and Maximum Protoflight/Qualification limits shown in Table 5-6.

Table 5-6 Temperature Limits at Fill and Drain Valve Mounting Interface

Minimum Temperature (ºC) Maximum Temperature (ºC) Operational (In Spec) +10 +50 Acceptance +5 +55 Protoflight/Qualification (In Spec)

0 +60

Survival -5 +65

Table 5-7 Propellant-wetted In-flight Software Temperature Limits

Software Temperature Limit Minimum Temperature (ºC) Maximum Temperature (ºC)

Green +10 +50

Yellow +6 +60

Red +5 +65

Note: Table 5-7 used for RST Software purposes only. Verification at these temperatures is not required, unless the temperature coincides with acceptance or protoflight/qual temperatures.

6 CLEANLINESS

The requirements in this section ensure the cleanliness of the Fill and Drain Valve at delivery, so as not to adversely affect its own performance, as well as not be a source of contamination to other items, including not generating contaminants following delivery in excess of that permitted below by virtue of its design, materials of construction, or operation.

6.1 Surface Contamination

Surface Contamination Levels at Delivery

6.1.1.1 External Surface Contamination

a. The Fill and Drain Valve external surfaces shall meet IEST-STD-CC1246E Particulate Cleanliness Level 300.

b. The Fill and Drain Valve external surfaces shall meet IEST-STD-CC1246E NVR Cleanliness Level R1.

c. The Fill and Drain Valve external surfaces shall also be visually inspected and meet VC- 0.5-1000 + UV per IEST-STD-CC1246E, or equivalent, when inspected with both UV and white light in a darkened room prior to delivery.

6.1.1.2 Internal Surface Cleanliness

a. The Fill and Drain Valve internal surfaces shall meet Particulate Level 50 per IEST-

STD-CC1246E.

b. The Fill and Drain Valve internal surfaces shall meet NVR Level R1 per IEST-STD-

CC1246E.

The interface tubes shall be protected from contamination at all times by the use of non-contaminating fittings and bagging, as required.

Surface Contamination Generation

6.1.2.1 Particulate Generation

The Fill and Drain Valve contractor shall not employ any of the following particle generating materials or processes into the Fill and Drain Valve design or construction without prior approval by the NASA GSFC COR:

• Paints prone to shedding due to large paint pigment molecules, overspray, poor adhesion, etc.

• Surfaces prone to corrosion or oxides because of a lack of corrosion protection or dissimilar metals in close contact.

• Fabrics with brittle constituents (e.g., composites, graphite or glass).

• Perforated materials when material is highly susceptible to tear propagation (e.g., multi-layer insulation (MLI)).

• Metal oxides (bare [untreated] aluminum and magnesium, iron, non-corrosion resistant steel, etc.).

• Braided metallic or synthetic wires, ropes, slings, etc. unless measures have been taken to contain any broken filaments or fibers (sheathing, sealing with polymers, covering, etc.).

• Woven materials especially cut or unfinished ends (metal braid, EMI shielding, lacing cord, expando sleeving), unless measures have been taken to prevent fraying or generation of particles (cut with a hot knife, seal with polymer, bag, etc.).

• Materials with thin films known to erode or crack or flake when subjected to normal handling (e.g., indium tin oxide [ITO] or other rigid or brittle semiconductor or ceramic coating on flexible substrates, Teflon, MLI, etc.).

• Foams, highly textured materials.

• Trapped debris in holes.

6.1.2.2 Molecular Generation

6.1.2.2.1 Material Selection

The Fill and Drain Valve materials shall have a total mass loss (TML) less than 1.00% and a collected volatile condensable mass (CVCM) less than 0.10%, when measured in accordance with ASTM E-595 unless a materials usage agreement has been generated and approved by the

NASA/GSFC COR.

6.1.2.2.2 Material Selection - Silicones

Silicones on external (to the spacecraft) surfaces shall not be exposed to the space environment unless approved by the NASA/GSFC COR. Silicones should be avoided or minimized. It is highly recommended that silicones be baked out at a high temperature prior to integration into the system to prevent extended bakeouts of the entire assembly.

Cleanability

6.1.3.1 Cleanability – Sensitive Surfaces

If any surfaces are not cleanable with Isopropyl alcohol and polyester wipes or light vacuuming, they shall be identified on the MICD.

6.1.3.2 Cleanability – Sensitive Surface Cleaning Methods

Alternate cleaning methods shall be identified and appropriate documentation provided for any surfaces that are not cleanable with Isopropyl alcohol.

6.1.3.3 Transportation Cleanliness

Materials and enclosure used for transportation and storage shall not generate molecular or particle contaminants or degrade the surface cleanliness of the item or adjacent items

7 DESIGN & CONSTRUCTION REQUIREMENTS

7.1 Parts, Materials & Processes (PMP)

Materials

The Fill and Drain Valve shall be comprised of materials and processes in accordance with the requirements in the SOW, RST-PROP-SOW-0052.

7.1.1.1 Material Conductivity

All parts should be passivated.

7.1.1.2 Lubricants

Lubricants used in the construction of the Fill and Drain Valves shall be compatible with hydrazine. Lubricants shall be approved by the NASA/GSFC COR.

7.1.1.3 Fluid Compatibility

a) The Fill and Drain Valves shall be fabricated with materials that are compatible with all fluids described below:

All internal surfaces of the Fill and Drain Valve within the fluid path, including all welds, shall show no degradation over the mission life stated herein to any of the following fluids:

• Gaseous Nitrogen per MIL-PRF-27401G

• Ultra High Purity Gaseous Helium per MIL-PRF-27407 D

• Hydrazine, per MIL-PRF-26536G

• Deionized and Distilled Water per JSC-SPEC-C-20C

• Isopropyl Alcohol per TT-I-735 (Grade A)

• Argon per MIL-PRF-27415C (Grade A)

7.1.1.4 Fill and Drain Valves Dewpoint

If water is used for testing purposes, the Fill and Drain Valves shall be dried to a dewpoint of -45°C.

7.2 Safety

All flight hardware shall meet the applicable section of the SOW, RST-PROP-SOW-0052.

7.3 Identification and Marking

Each unit shall be permanently marked with the part number and a unique sequential serial number in the area designated on the interface control drawing in a manner to be approved by the

NASA/GSFC COR.

All markings shall use alcohol proof ink, engraving, or laser etching.

The Fill and Drain Valve shall be marked to include but not limited to the following, Vendor Part number Vendor Name Vendor Serial Number Contract Number Gas or Liquid

7.4 Workmanship

Workmanship Standards

The workmanship standards and processes outlined in the RST-PROP-SOW-0052 shall be used.

Welding

All welds shall be performed and inspected according to a vendor procedure approved by NASA GSFC COR and in compliance with the SOW, RST-PROP-SOW-0052.

Test record such as dye penetrant, x-rays, etc. shall be retained.

7.5 Reliability and Mission Lifetime

Mission Life

The Fill and Drain Valve shall meet all performance specifications through three (3) years of ground testing and five (5) years of operation in space, following a three (3) month commissioning period.

Shelf Life

The Fill and Drain Valve shall not suffer any degradation in performance when stored for five

(5) years either on the S/C or in bonded storage

7.6 Ground Handling

GSE Cleanliness

All Ground and Test support equipment shall be compatible with the flight component and the environment where the flight component or test component will reside (cleanroom, thermal vacuum chamber, vibration cell, etc.). For delivery, marked non-flight finger removable GSE protective caps shall be provided on tube ends to maintain internal cleanliness and protect the tube ends. Verify no additional non-flight material shall be placed inside the item just prior to delivery.

7.7 Interchangeability

Each Fill and Drain Valve shall be directly interchangeable in form, fit, and function with other items of the same part number.

8 MECHANICAL DESIGN REQUIREMENTS

For additional guidance on the design and analysis of threaded fastening systems in NASA spaceflight hardware, consult NASA-STD-5020A, “Requirements for Threaded Fastening Systems In spaceflight Hardware”.

8.1 Mechanical Factors of Safety

Positive Margin of Safety (MS) shall be demonstrated analytically for Fill and Drain Valve including interfaces to MGSE, using the MS formula below with the appropriate Factors of Safety (FS) defined in Table 8-1 applied to flight limit loads.

Note:

1. MS is defined as follows:

𝑀𝑀𝑀𝑀 =

𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴 𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿 𝐿𝐿𝐴𝐴𝐴𝐴𝐿𝐿 𝐴𝐴𝑜𝑜 𝑀𝑀𝐿𝐿𝑜𝑜𝐴𝐴𝑆𝑆𝑆𝑆

𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐴𝐿𝐿𝐴𝐴𝐿𝐿 𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿𝐿 𝐿𝐿𝐴𝐴𝐴𝐴𝐿𝐿 𝐴𝐴𝑜𝑜 𝑀𝑀𝐿𝐿𝑜𝑜𝐴𝐴𝑆𝑆𝑆𝑆 ∗ 𝐹𝐹𝑀𝑀

− 1

2. Positive MS in joints that are both bonded and fastened is demonstrated assuming only the bond carries the load, only the bolt carries the load, or if the capability of the joint requires both the bond and fasteners, a detailed analysis is performed.

a. The adhesive portion of the joint is usually the stiffest load path and thus carries most of the load. In this scenario, the full strength of the bolted interface is not realized until after the failure of the adhesive.

3. Positive MS is demonstrated for adhesively bonded joints for all potential failure modes under all loading conditions and temperatures.

a. Failure modes may include cohesive failure in the adhesive, failure at the adhesive to adhered interface, and adherent failure. Composite adherent failure modes may include in-plane tension/compression, in-plane shear, peel, interlaminar shear, and interactions between failure modes.

b. Fiber orientation should be considered in the computation of strength for a bonded joint where one or more of the adherends are made of composite material.

c. Interaction between adhesively bonded joints in close proximity should be included when analyzing bonded joints.

d. Temperature stresses in bonded joints and sandwich panels should consider bond and consolidation cure temperatures.

e. Adhesive bond fillets and bondline thickness should be considered in bonded joint design and analysis under temperature loading.

Table 8-1 Design Factors of Safety

Type of Hardware Static /Sine Random/Acoustic 3,4

Tested Metallic Yield 1.252 1.6 Tested Metallic Ultimate 1.42 1.8 Stability/Buckling Ultimate 1.4 1.8

Type of Hardware Static /Sine Random/Acoustic 3,4

Beryllium Yield 1.4 1.8 Beryllium Ultimate 1.6 2.0 Composite Ultimate1 1.5 1.9 Bonded inserts/Joints Ultimate 1.5 1.9 Glass/Ceramic 3.05 3.8 Bond in Glass/Ceramic 1.5 1.9

(1) All composite structures must be tested to 1.25 x limit loads.

(2) For qualification by analysis only, positive margin must be shown with FS of 2.0 and 2.6 for metallic yield and ultimate, respectively.

(3) Factors shown are applied to statistically derived peak response based on limit/acceptance RMS level. As a minimum, the peak response must be calculated as a 3-sigma value.

(4) Factors shown assume that qualification/prototype testing is performed at 3dB above limit/acceptance limits. If the difference between acceptance and qualification is less than 3dB then the above factors may be applied to qualification minus 3dB.

(5) For qualification by analysis only, a no-test safety factor of 5.0 may be used for glass (not ceramic), per NASA-STD-5001B Table 3.

8.2 Fracture and Fatigue

Propulsion System Fill and Drain Valves must be evaluated for fracture criticality. Propulsion System Fill and Drains are included under tier 4 of a four-tier system used to evaluate fracture criticality of hardware; tier 4 has associated mitigation requirements that shall be followed, as specified below.

Tier 4 fracture classification: Fracture control requirements (per NASA-STD-5019) shall apply to the following elements only: (1) Pressure vessels, dewars, lines, fittings and other pressurized components (per NASA-STD 8719.24); (2) Castings (unless hot isostatically pressed and the flight article is proof tested to 1.25 times limit load); (3) Weldments; (4) Parts made of materials in Tables II or III of MSFC-SPEC-3029A if under sustained tensile stress; (5) Parts made of materials susceptible to cracking during quenching; (6) Nonredundant, mission-critical preloaded springs loaded to greater than 25 percent of ultimate strength.

Notes for fracture/fatigue:

1. Fracture analysis is performed assuming an initial crack size. NDE or proof testing is required to verify this initial crack size assumption. If proof testing, the proof tests must be at load sufficient enough to screen for any crack size above the assumed. This often results in over-test compared to DLL.

2. If NASGRO is used for brittle component fracture analysis, the NASGL module is used.

3. A fail-safe component is a structural component in a redundant load path which after the loss of the component, the remaining load path(s) has sufficient structural capability to withstand the redistributed loads, and the loss of the component will not cause a catastrophic hazard.

Examples of redundant load paths are multiple fasteners in bolted joints, stitched welded structures, and riveted and bolted structures. A factor of safety of 1.0 shall be applied to the remaining load path(s) when demonstrating fail-safe.

4. Critical fastened joints are joints whose failure results in mission-ending failure. Class-C fasteners that are contained within Class-C hardware are not critical fasteners.

5. Mission cycles include ground testing and handling, transportation, launch, and on orbit loading. The load spectrum will include the load level and the accompanying number of cycles and duration (for static loading) at each level during the hardware service life. Mission cycle load spectrum is included in the Fracture Control Plan.

6. In cases where fracture toughness of a metal is not known, contact RST project for help in fracture classification.

8.3 Metallic Pressurized Lines and Fittings Burst Factor

Metallic pressurized lines and fittings shall be designed to sustain the design Burst Pressure (BP) as defined in notes without leakage or rupture.

Notes:

1. Burst Pressure is defined as follows:

𝐵𝐵𝐵𝐵 = 𝐵𝐵𝐵𝐵𝑜𝑜𝑆𝑆𝐿𝐿 𝐹𝐹𝐴𝐴𝐹𝐹𝐿𝐿𝐴𝐴𝑜𝑜(𝐵𝐵𝐹𝐹) 𝑥𝑥 𝑀𝑀𝐴𝐴𝑥𝑥𝐿𝐿𝐿𝐿𝐵𝐵𝐿𝐿 𝐸𝐸𝑥𝑥𝐴𝐴𝐴𝐴𝐹𝐹𝐿𝐿𝐴𝐴𝐿𝐿 𝑂𝑂𝐴𝐴𝐴𝐴𝑜𝑜𝐴𝐴𝐿𝐿𝐿𝐿𝑂𝑂𝑂𝑂 𝐵𝐵𝑜𝑜𝐴𝐴𝑆𝑆𝑆𝑆𝐵𝐵𝑜𝑜𝐴𝐴(𝑀𝑀𝐸𝐸𝑂𝑂𝐵𝐵)

Burst Factor (BF) for diameter ≥ 1.5 in = 2.5, BF for diameter < 1.5 in = 4.0

8.4 Materials

Dissimilar Metals

Dissimilar materials in direct contact with each other shall be compatible as defined in Table I of MIL-STD-889C, unless approved by the Parts, Materials and Processes Control Board.

Note:

1. Use of similar materials sealed per NASA-STD-6012 may be acceptable in some instances.

Material Allowables and Stiffness Material allowables and stiffness shall be:

a) At least A-basis for metallic materials as defined in MMPDS or B-basis values tested under the appropriate environments.

b) At least B-basis for composite materials as defined in CMH-17, or B-basis values tested under the appropriate environments and representative of the processes used in the fabrication of the components while accounting for strength degradation due to thermal cycles.

c) B-basis values for glass/ceramics based on Weibull distribution, or using a test verified threshold stress, or a value of 6.9 MPa (1 ksi). Used in the absence of test data).

Note:

1. A and B basis statistics apply to material allowables only.

CTE Data Coefficient of Thermal Expansion (CTE) data for materials shall be tested or obtained for the range of maximum survival temperature down to minimum survival temperature.

Note:

1. Obtained data requires project approval for use.

Stress Corrosion Cracking All metallic materials shall be selected from Table I of MSFC-STD-3029, unless otherwise approved by Parts, Materials, and Processes Control Board.

8.5 Joints

Joint Edge Distance

The minimum bolt edge distance shall be as specified in Table 8-2 unless a detailed analysis is performed to justify otherwise.

Notes

1. Use appropriate bearing value from MMPDS for metals

2. D = Bolt hole or insert sleeve diameter, e = edge distance from center of bolt to edge of panel

Table 8-2 Minimum Edge Distance

Minimum Edge Distance (e/D) Composite/Ceramic 2.5 min

Metallic 1.5 min

Bonded Joint Allowable Bonded joint allowables shall be B-basis produced through coupons representative of flight hardware, tested under their appropriate environments, and taking into account strength degradation due to thermal cycles.

Rationale: Bond strength is dependent on materials and workmanship, e.g. surface prep. Due to scatter from the workmanship process and material variability, B basis allowables are developed for structural analysis.

Note: Bonded joints on flight hardware are proof tested to 1.25 times limit load.

Reserved Fastened Joints

8.5.4.1 Fastener Locking

Each threaded fastening system in spaceflight hardware shall incorporate a minimum of one locking feature that does not depend upon preload to function.

Notes:

1. Locking features and their installation processes, including verification methods, should be specified in the engineering documentation.

2. Locking features should be verifiable per Section 4.6.4 of NASA-STD-5020A.

8.5.4.2 Fastened Joint Margin of Safety

Positive MS for all threaded fastening systems shall be demonstrated for:

a) Ultimate design loads under all structural failure modes in conjunction with the applicable maximum expected range of environmental conditions without failure.

b) Yield design loads in conjunction with the applicable maximum expected range of environmental conditions without detrimental yielding.

1.

c) Gapping load in conjunction with applicable maximum or minimum temperatures without gapping.

1)

See NASA-STD-5020A, section 4.4.1 as reference.

8.5.4.3 Installation Torque Documentation

Engineering documentation shall specify the installation torque range or specify an applicable standard that defines the installation torque range.

Note:

1. The engineering documentation should clearly identify when the installation torque is the torque above running torque.

8.5.4.4 Seal Analysis

For a joint that maintains a seal (e.g., to maintain pressure or contain a fluid), the seal shall meet its requirements at the design separation load when assuming minimum preload for all fasteners in the joint.

8.5.4.5 Critical Fasteners

Fastened joints identified as critical shall be demonstrated as either safe-life or fail-safe.

Notes:

1. Critical joints will be identified with project concurrence. Critical joint’s failure lead to mission ending failure.

2. A safe-life component is a structural component which can be demonstrated to have at least 4 design life cycles under all anticipated load environments, including integration, testing, ground transport, and launch. Industry standard methods such as linear-elastic fracture mechanics using NASGRO® or S-N fatigue analysis curves may be used for analytically demonstrating safe-life. NDE is required for substantiating initial crack size in linear-elastic fracture analysis.

3. A fail-safe component is a structural component in a redundant load path which after the loss of the component, the remaining load path(s) has sufficient structural capability to withstand the redistributed loads, and the loss of the component will not cause a catastrophic hazard. Examples of redundant load paths are multiple fasteners in bolted joints, stitched welded structures, and riveted and bolted structures. A factor of safety of

1.0 shall be applied to the remaining load path(s) when demonstrating fail-safe.

9 LOGISTICS

9.1 Transportation Cleanliness

Materials and enclosure used for transportation and storage shall not generate molecular or particle contaminants or degrade the surface cleanliness of the item or adjacent items

9.2 Transportability

The Fill and Drain Valve shall be designed so as to be capable of being handled and transported to GSFC without degradation or damage.

9.3 Transportation Equipment

Reference section 7.0 of the SOW (RST-PROP-SOW-0052) for specific requirements

10 VERIFICATION REQUIREMENTS

The contractor shall conduct a verification program that demonstrates the component design is qualified. Per the SOW (RST-PROP-SOW-0052), the contractor will provide a verification matrix defining the method of verification for each specific requirement of this document.

10.1 Verification Methods

Verification methods include inspection, analysis, as well as environmental, functional, and performance testing, or a combination of these techniques.

Inspection

Verification by inspection includes (but is not limited to) visual inspection, simple physical manipulation, gauging, measurement, and documentation examination.

Analysis

Verification by analysis will be used to show design margins. Also, when the particular tests required for verification are impractical, risky, unacceptably long, or prohibitively expensive, analysis may be used instead of testing, as noted in the verification matrices.

Analysis, including simulations where applicable, will also be used to guarantee that the Fill and Drain Valve and its components will perform as expected under worst-case conditions.

Test

Verification by test includes, but is not limited to, the evaluation of performance by use of special equipment or instrumentation, simulation techniques, and the application of established principles and procedures to determine compliance with requirements.

10.2 Inspection Requirements

Verification by inspection shall be by one of these three methods: 1) visual inspection of the physical component; 2) a physical measurement of a property of the component, or; 3) a documentation search demonstrating components of an identical design has demonstrated fulfillment of a requirement.

Visual Inspection

Visual inspection of the physical component shall be performed by a qualified inspector to certify that the component has the properties/configuration specified in the requirement.

Physical Measurement

Physical measurement of component property (i.e. mass, dimensions, etc.) shall be performed by a qualified inspector to demonstrate the component meets specific requirement.

Documentation Search

Verification of requirements based on similarity shall include supporting rationale and documentation and be approved by the NASA/GSFC COR.

10.3 Analysis Requirements

Verification of performance or function through detailed analysis, using all applicable tools and techniques, is acceptable with NASA/GSFC COR approval. Detailed descriptions of the minimum required analyses, as well as analysis requirements, are provided in the SOW.

10.4 Test Requirements

This section provides general test requirements on how testing is to be performed in the process of verifying that the deliverable item meets its requirements.

a. Performance parameter measurements shall be taken to establish a baseline that can be used to assure that there are no data trends established in successive tests that indicate a degradation of performance trend within specification limits that could result in unacceptable performance in flight.

b. Any requirement that exceeds previous qualification test data shall be presented to the

NASA/GSFC COR as part of the verification planning process described in the SOW, for evaluation and a possible delta qualification test.

Definitions

The hardware definitions are reproduced here from Section 1.8 of GEVS (GSFC-STD-7000A).

Prototype Hardware: “Hardware of a new design; it is subject to a design qualification test program; it is not intended for flight.” The purpose of the tests on this hardware is to prove that a new design meets one or more of its design requirements. Qualification testing is performed at maximum expected flight levels plus a margin. Test durations are typically longer than for acceptance tests.

Protoflight Hardware: “Flight hardware of a new design; it is subject to a…